Adherence to antiretroviral medications in HIV: differences in data collected via self-report and electronic monitoring.

Controversy remains regarding the reliability of methods used to determine adherence to antiretroviral medication in HIV. In this study the authors compared adherence rates of 119 HIV-positive participants during a 6-month study, as estimated via electronic monitoring (EM) and self-report (SR). Adherence for both short (4-day) and long (4-week, or intervisit) periods was examined, as well as factors that underlie discrepancies between EM and SR. Results showed that intervisit EM estimates were consistently lower than those of SR. SR estimates based on shorter periods (4 days) were closer to those of EM. Higher discrepancies between EM and SR estimates were associated with lower cognitive functioning and externalized locus of control. These findings lend support for using both EM and SR methods; however, study design (e.g., length) and other factors (e.g., cognitive status, cost) should be considered.